1967-'68 Pontiac Firebird 400

Buyer's Guide from Hemmings Muscle Machines

Among the many ways that Pontiac attempted to differentiate its new Firebird from the Camaro was to offer the Firebird in five different flavors, rather than one basic model that could be tarted up with à la carte options. For 1967 and 1968, Pontiac even used variations of the tagline, "The Magnificent Five... the Pontiac Firebirds," to tout its new pony car and its five different option packages.
Of course, true gearheads looked to the top version first. Base six-cylinder? No. Hotted-up overhead-cam six-cylinder? Getting warm. The 250hp 326 V-8? Good for secretaries. Firebird H.O., with 30 more horses out of its 326? If you're on a budget, sure.
Instead, it was the Firebird 400 that got an eager buyer's testosterone flowing, with its bigger V-8, dual exhaust, heavy-duty transmissions and suspension upgrades.
To the base Firebird coupe's $2,666 purchase price, the Firebird 400 package added another $274 (in 1968, prices rose to $2,781 and $351, respectively), though adding all the respectable performance options could jack the tally up to nearly $4,000. Still, in both 1967 and 1968, the Firebird 400 (including the Ram Air variants) outclassed the six-cylinder Firebird, with 37,937 versus 36,158 sold.
The 400 V-8 and the Firebird 400 package did continue into 1969, but the Firebird itself changed substantially enough that year to warrant its own separate consideration. So if you're considering buying a 1967-1968 Firebird 400, here's what you should look for.
ENGINES
One of GM's many corporate edicts in the 1960s restricted the maximum output of any production car to one horsepower per 10 pounds. With a target weight of 3,250 pounds for the 1967 Firebird 400, that meant Pontiac would have to restrict the 400-cu.in. V-8 to 325hp.
Faced with a shortened development cycle for the 1967 introduction, Pontiac engineers simply nabbed the L78 335hp 400 from the GTO and renamed it the W66. The two shared every aspect of their build, from bore and stroke (4.12 inches by 3.75 inches) to the 10.75:1 compression ratio to the "670" heads with 2.11-inch intake valves and 1.77-inch exhaust valves, to the "067" camshaft with 273 degrees intake duration and 289 exhaust (on four-speed models; automatics used the "066" cam with 273/282 degrees duration, intake and exhaust).
The only difference, according to Jim Mattison of Pontiac Historical Services, was a slightly different throttle linkage that prevented the Rochester Quadrajet's secondaries from opening more than 90 percent. ("It just needed to be bent a little bit to open the secondaries up all the way," Jim told us. "It took all of 20 seconds.") With the new throttle linkage, Pontiac could officially rate the Firebird 400's engine at 325hp at 4,800 RPM and 410-lbs.ft. of torque at 3,600 RPM.
The W66 did benefit from a bit of underhood chrome: The louvered "pancake" air cleaner, rocker-arm covers, oil cap and breather were all plated. A heavy-duty cooling system, battery and starter accompanied the W66.
For 1968, the same basic 400 remained, now rated at 330hp at 4,800 RPM and 430-lbs.ft. of torque at 3,300 RPM, and equipped with "16" cylinder heads; "62" heads were used on some automatic cars. Pontiac also added the L74 400 H.O. engine, using the "067" cam on automatics and the 288/302-duration "068" on manuals, both rated at 335hp.
For an additional $263.30, 1967's Firebird 400 buyer had the option of ordering the L67 Ram Air package, which ostensibly upped the output to 335hp at 5,200 RPM. Pontiac accomplished this not only by opening up the hood scoops and ducting them to an open-element air cleaner, but also by swapping for the "997" heads, bolting on the low-restriction cast-iron exhaust manifolds from the 428, adding a calibrated Quadrajet and slipping in a "744" camshaft with 301 degrees of intake duration and 313 degrees exhaust. The same combination in the GTO Ram Air was worth 360hp, but the altered throttle linkage from the W66 kept the Firebird Ram Air engine from its full potential.
The Ram Air package returned in 1968; now equipped with "31" heads and an "068" cam, it was still rated at 335hp. Late in the model year, it was replaced with the Ram Air II, officially rated at 340hp, which benefited from a four-bolt main block, forged pistons, an Armasteel nodular iron crank, round-port R-96-A heads and an "041" camshaft (308 degrees of intake duration, 320 exhaust).
Unfortunately, neither the Vehicle Identification Numbers nor the cowl tags for 1967 and 1968 Firebirds indicate exactly which engine Pontiac originally planted in a car. However, both do indicate whether the car originally had a six-cylinder or V-8 engine--look for a 1 in the eighth digit of the VIN or for 22437 or 22637 on the third line of the cowl tag to identify a V-8 car. And in 1968, Pontiac did start stamping a portion of the VIN into the engine--look for a 2 followed by the last eight digits of the VIN vertically up the block alongside the timing cover.
All Pontiac V-8 engines of this period had two-letter engine block codes stamped onto the front passenger's side of the block below the cylinder deck, indicating not only year of manufacture, displacement and power output, but also what model it was originally installed in.
Pontiac restorer Scott Tiemann of Super Car Specialties in Portland, Michigan, said all Pontiac engines of this era were notorious for timing chain issues, caused by nylon teeth on the camshaft gear. He pointed out, however, that this only applies to original engines; all aftermarket timing chain sets come with all-steel camshaft gears.
TRANSMISSIONS
While every other Firebird used a Saginaw three-speed manual as a base transmission, the Firebird 400 used a heavy-duty Dearborn three-speed with a 2.42:1 first gear ratio, sourced from Ford Motor Company. The optional Muncie M20 four-speed manual also backed both the 326 and 326 H.O.-powered Firebirds for that year. For 1968, Muncie's close-ratio M21 joined the M20 on the option sheet.
For fans of automatic transmissions, Pontiac offered the three-speed Turbo Hydra-Matic 400 both years.
Neither the VIN nor the cowl tag indicated the original transmission, but as with the engine, Pontiac did start stamping a partial VIN on the transmission in 1968--for manual transmissions, look on the passenger's side of the case; for automatic transmissions, look on the driver's side. The two-letter engine code stamped on the engine block will also indicate whether a manual or automatic transmission backed that engine.
DIFFERENTIAL
The 1967 Firebird 400 could have come with any of the Firebird's range of rear gear ratios in the B-O-P 10-bolt differential, from a 2.56 through a 3.90. Firebird 400 buyers who ordered a 3.90:1 gear ratio--which was required with the Ram Air version--could only get that ratio with a Saf-T-Track limited-slip differential. The two-letter rear axle code is stamped on the rear of the driver's side axle tube.
Differentials for 1968 Firebird 400s remained mostly the same, with only a few minor changes. First, Pontiac introduced a heavy-duty four-pinion differential for all rear axles with 3.36 and deeper gears (numerically lower gears still used a two-pinion differential); second, Pontiac added a 4.33:1 rear axle ratio to the option sheets.
Scott noted that the original Saf-T-Track limited-slip differential wasn't as strong as it could have been. "You're gonna bust one in short order if you have a four-speed and slicks," he said. For street use, it was adequate, but racers should consider upgrading to a stronger limited-slip.
FRAME AND SUSPENSION
Like the Camaro and the 1968 and up Chevy II/Nova, the Firebird used a mostly unit-body chassis structure with a stub frame ahead of the firewall, coil-sprung front suspension and leaf-sprung rear suspension. All 1967 Firebird 400s benefited from the ride and handling package, which was optional on other Firebirds and included stiffer 345-pound-per-inch front springs and 135-pound-per-inch monoleaf rear springs to go with the 0.6875-inch front anti-roll bar. All V-8-powered Firebirds equipped with an automatic transmission received a traction bar on the passenger's side to stop axle hop; those with a manual transmission received traction bars on both sides.
For 1968, the Firebird 400 did away with the traction bars, monoleaf springs and inline shock absorber setup in favor of multi-leaf springs and staggered shocks.
The weakest link in the rear suspension, according to Scott, tends to be the 5/16-inch centering bolt for the leaf springs. "If you do any kind of hot rodding, it's gonna shear off," he said. He recommended replacing it with a larger 7/16-inch bolt.
BRAKES
As was the custom of the time, non-power hydraulic drum brakes--on the Firebird, measuring 9.5 inches--came standard on all four corners. Firebird buyers could option up either power-assist drum brakes or 11-inch, four-piston front disc brakes, with or without power-assist. As with the Camaros, the four-piston disc brakes proved troublesome, prone to leaking and hard to get parts for. The single-piston disc brakes used on Firebirds starting in 1969 are a simple swap, and a number of aftermarket companies offer single-piston swap kits.
WHEELS AND TIRES
Pontiac partly marketed its Firebird 400 package on the Firestone E70-14 Wide- Oval redline tires that came standard with the package, mounted on either steel wheels with hubcaps, Rally I or Rally II wheels, all measuring 14 x 6 inches. In 1968, E70-14 white stripe tires became a no-cost option.
BODY AND INTERIOR
At a glance, differentiating 1967 and 1968 Firebirds is rather simple, despite their nearly identical sheetmetal. First, look for the vent windows on 1967 Firebirds and for one-piece glass--with the advent of flow-through ventilation--on 1968 Firebirds. Second, thanks to the National Traffic and Motor Vehicle Safety Act, look for side-marker lamps on the rear quarters of 1968s, which also used new wraparound front parking lenses, incorporating the side markers.
The big distinguishing feature of Firebird 400s, the twin-nostril hood, remained non-functional unless the Ram Air package was ordered, in which case the hood was opened up and sealed to the air cleaner. A "400" badge rested on either side of the hood and on the right side of the trunklid, but otherwise, the Firebird 400 remained free from stripes and graphics. For some reason, Pontiac decided that only 400 models would receive the big arrowhead in the center of the front bumper--other Firebirds have no bumper emblem.
Decoding the VIN on 1967-'68 Firebirds is rather simple. The first five digits should read 22337 for coupes, 22367 for convertibles. The sixth digit is the year, and the seventh digit is the assembly plant: Lordstown, Ohio, (U) in 1967 and 1968; or Van Nuys, California, (L) in 1968. On the cowl tag, the second line indicates the car's assembly date, while the fourth line indicates the car's original interior trim, paint color and select options.
On all Firebird convertibles, a pair of trunk-mounted canisters were supplied to dampen body vibration; two more canisters should be up front. Commonly called cocktail shakers, these canisters contained spring-mounted weights suspended in oil. Convertibles also came from the factory with a special bolt-on underbody reinforcement plate that often goes missing if a car has had transmission or exhaust work.
Scott noted that rust can develop in pretty much any typical section of sheetmetal, but warned to check the rear subframes in particular for rot. "The subframes aren't much thicker than normal sheetmetal, and though a lot of that area was galvanized, they still can get rusty," he said.
RESTORATION AND PERFORMANCE PARTS
Though Firebird enthusiasts surely get tired of the Camaro comparisons, the close relationship between the two means that the Firebird benefits from the Camaro's broad support in the restoration aftermarket. "There's nothing we need to source OEM," Scott said. The Firebird also benefits from support from Pontiac-only parts suppliers such as Ames Performance Engineering and from muscle car parts houses such as Year One and Original Parts Group.
Owner's view
We bought this original 1968 Pontiac 400 in March 2007. Taking my car out to local events is often quite interesting. Many guys closely examine my Firebird. They are usually focused on the untouched details, like the original overspray on my hood's underside, factory crayon-type dash details and other interior components, and often use them as reference material for their own restorations.
One of the car's main points of interest to me pertains to its originality. I like and appreciate the factory paint because it was hand-sprayed, unlike today's use of robotics. The original seats have a special broken-in feeling that newer ones don't include. Even my Firebird's interior smells intriguing, not like some brand-new vinyl from a local shop.
Sometimes nothing compares to how the factory built cars. It is, as they say, only original once.--Steve Wise
Club scenePontiac Oakland Club International
P.O. Box 68
Maple Plain, Minnesota 55359
877-368-3454www.poci.org
Dues: $35/year • Membership: 8,800
National Firebird and Trans Am Club
P.O. Box 11238
Chicago, Illinois 60611
773-769-6262www.firebirdtaclub.com
Dues: $35/year
What to pay